Active matrix liquid crystal display with black-inserting circuit

Abstract

An active matrix LCD ( 200 ) includes: a plurality of scanning lines ( 23 ) that are parallel to each other and that each extend along a first direction; a plurality of signal lines ( 24 ) that are parallel to each other and that each extend along a second direction orthogonal to the first direction; a plurality of thin film transistors (TFTs) each provided in the vicinity of a respective point of intersection of the scanning lines and the signal lines; a plurality of scanning line driving circuits ( 21 ) for providing a plurality of scanning signal groups to the scanning lines, each scanning signal group including an image scanning signal and a black-inserting scanning signal; a plurality of signal line driving circuits ( 22 ) for providing gradation voltage data to the signal lines; and a black-inserting circuit ( 28 ) for providing black-inserting signals corresponding to black image data to the signal lines.

1 . An active matrix liquid crystal display (LCD), comprising: 
 a plurality of scanning lines that are parallel to each other and that each extend along a first direction;    a plurality of signal lines that are parallel to each other and that each extend along a second direction orthogonal to the first direction;    a plurality of thin film transistors (TFTs) each provided in the vicinity of a respective point of intersection of the scanning lines and the signal lines;    a plurality of scanning line driving circuits for providing a plurality of scanning signal groups to the scanning lines, each of the scanning signal groups including an image scanning signal and a black-inserting scanning signal;    a plurality of signal line driving circuits for providing gradation voltage data to the signal lines when an image scanning signal is provided to the scanning lines by the scanning line driving circuits; and    a black-inserting circuit for providing black-inserting signals corresponding to black image data to the signal lines when black-inserting scanning signals are provided to the scanning lines by the scanning line driving circuits.    
   
   
       2 . The active matrix LCD as claimed in  claim 1 , wherein the black-inserting circuit includes a plurality of transistors, an enable port providing an enable signal to activate the transistors, and a polarity control circuit providing black-inserting signals to the signal lines through the transistors when the transistors are in an activated state.  
   
   
       3 . The active matrix LCD as claimed in  claim 2 , wherein the polarity control circuit includes two control pins, a first output pin connected to odd-numbered signal lines through respective of the transistors, and a second output pin connected to even-numbered signal lines through respective other of the transistors.  
   
   
       4 . The active matrix LCD as claimed in  claim 3 , wherein the control pins of the polarity circuit are used to control the polarity of the black-inserting signals, and apply the black-inserting signals to the signal lines.  
   
   
       5 . The active matrix LCD as claimed in  claim 1 , further comprising a timing control circuit used to provide clock signals having a steady period.  
   
   
       6 . The active matrix LCD as claimed in  claim 5 , wherein the image scanning signal and the black-inserting scanning signal are pulse signals.  
   
   
       7 . The active matrix LCD as claimed in  claim 6 , wherein a duration of each image scanning signal plus a duration of each black-inserting scanning signal is equal to one clock period.  
   
   
       8 . The active matrix LCD as claimed in  claim 7 , wherein the duration of each image scanning signal is equal to the duration of each black-inserting scanning signal.  
   
   
       9 . The active matrix LCD as claimed in  claim 7 , wherein the duration of each image scanning signal is longer than the duration of each black-inserting scanning signal.  
   
   
       10 . The active matrix LCD as claimed in  claim 7 , wherein the duration of each image scanning signal is shorter than the duration of each black-inserting scanning signal.  
   
   
       11 . The active matrix LCD as claimed in  claim 1 , wherein each of the scanning signal groups has a duration equal to half of a frame time.  
   
   
       12 . The active matrix LCD as claimed in  claim 1 , wherein each of the scanning signal groups has a duration equal to two fifths of a frame time.